Power operated clipping shears



Nov, 10, 1959 c. J. HOPKINS POWER OPERATED CLIPPING SHEARS Filed April 9, 1958 United States Pate POWER OPERATED CLIPPING SHEARS Celestin J. Hopkins, Port Angeles, Wash.

Application April 9, 1958, Serial No. 727,480

4 Claims. (Cl. 30-228) The present invention relates to certain new and useful improvements in a powered hand-tool in the form of double blade cutting or clipping shears expressly, but not necessarily, adapted for cutting and trimming the marginal portion of grass on ones lawn.

`There has existed a long felt need for a practical, positive-action powered hand tool for cutting grass. Manifestly, if not too complicated or too expensive, such a tool would be welcomed, to say the least, by most home owners. After much thought `and a survey of those types of tools in the category under consideration which are` most acceptable and usable, it is plain to be seen that the most satisfactory and successful way of cutting grass is with the form of tool having openable and closable shears or cutting blades. When done by hand the job is vtedious and laborious. lIt lfollows that the instant concept has to do with an efficient power activated scissors-type clipping tool. To this end it has been decided t eliminate the crossed-type scissors and toY concentrate on powering two-bladed shears wherein the blades are not crossed but are hinged on a handle and are joined together and activated bya blade opening and closing pin and a novel push-pull rod therefor.

Preliminary approaches kept involving powered action of various types to pull the blades closed and to open them with simple spring means. It was found that the closing action was usually slower than 'the opening action. However, what is wanted is the reverse so that the blades shut quicklyV and open progressively butV deliberately. The danger of the user being injured by blades that are closed by powered action is apparent and appreciated. It is also realized that such powered cutting blades when closing on some foreign object or by way of clogging material therebetween would continue to close until the prime mover, usually an electric motor, stalls or some part of the linkage or mechanism breaks.

These and other lines of thought gave rise to designing the present invention in the rm belief that its action is basically correct whenthe powered action cycle or` stage is used only to open the blades and reset a springtriggered push-pull rod the function and action of which serves to close the blades. So constructed and made the improved shears can never become cloggedor stopped up by anything that cannot be cut through but will immediately open again to release the obstruction or to enable one to try again to cut it. The closing action powered only by a spring is a quick, safe construction and reliable method of clipping. The clipping action can be adjusted to a wide range of spring tensions and the cutting blade slots or openings adjusted and positioned to suit the material being cut or to suit the safety conscious expectations of the cautious user.

In carrying out a preferred embodiment of the invention a suitable hollow handle is provided. This handle is of a shape and size to be conveniently graspedand used. A pair of complemental cutting blades are hingedly mounted at their inward ends on the distal or outer end of the handle. An encased prime mover, an electric1 motor for example, is mounted for operation on the proximal or inner end of the handle. i means is provided between the prime mover 'and blades, said means serving irst to spread and open the blades by power delivered positively and directly from the prime mover to the blades and serving, secondly, and intermittently to quick-c1ose the blades during which closing step or movement the power cycle and 'attending drive-action is momentarily released, whereby the blades are opened progressively but deliberately and yet are closed speedily and lquickly without ever overloading or damaging the motor and the connection of the motor to the blades.

More explicitly novelty is Ipredicated Iupon the means stated above which embodies a power-pushed spring retracted push-pull rod mounted for reciprocation` in the handle and having its forward end pivotally joined to overlapping cooperating inner end portions of the blades with the overlapping portions in axial alignment with the handle and with the hinged portions to the right and left of the pivoted overlapping portions.

Other objects, features and advantages will become more readily apparant from the following description and the accompanying drawing.

In the drawing, wherein like numerals are employed to designate like parts throughout the views:

Fig. l is a bottom plan view with portions broken away and appearing in section and wherein all of the com# ponents and their association and arrangement is illustrated, making up the automatically operable shears herein under consideration;

Fig. 2 is a side or edge view of the construction seen in Fig. 1 and with portions` of the gear box or motor housing broken away; and j Fig. 3 is a view partly in section and partly in elevation showing the lbifurcated end of the push-pull rod and how the overlapped portions of the cutting blades are operatively pivoted between the furcations.

Referring now to the drawing the hollow cylindrical handle seen in Figs. l and 2 is denoted at 6 and has an open 'ended bore. There is an outstanding lateral llange 8 at the proximal or inward end. There is a suitable head 1li at the forward or distal end and the head is preferably in the form of a fork and the arms of the fork are denoted by the numerals 12 and 13. As better shown in Fig. 2 the outer ends of the arms are bifurcated and the furcations 14 and 15 straddle the adjacent end portions 16 of the paired cutting blades or shears 17 and 18. The end portions 16 are mounted hingedly by the headed hinge pins 20 held in place by cotter keys 2,2. It follows that the blades 17 and 18 are thus hinged on the arms of the fork head to the left and right of the axis of the bore 24 of the handle. At the juncture of the head and handle the bore is internally screw threaded as at 26 to accommodate the external screw threads on a bushing 23 which is screwed in place in the manner seen in Fig. 1 and which has a suitably made nger-grip accessible at 30. TheI tapering of the fork arms as seen in Fig. 2 makes it easy to catch hold of and to turn the bushing. The bushing in turn provides a bearing for a cooperating portion of the push-pull rod or plunger 32. This rod is of a length greater than the length of the bore and the inner end portion 34 projects to the right beyond the bore as seen in Fig. l. suitably secured by a setscrew or the like on the push rod and confined in the bore and movable toward and from cushioning washers or the like 3ft which partially absorb shock. The required coil spring 40 is confined in the bore and encircles the rod and bears at one end against the collar 36 Vand atv the other end against the bushing. By adjusting the bushing the tension of the coil spring can be regulated as is obvious. The projecting end portion of the push-pull rod is bifurcated as shown and the turca Novel operating Adjacent to this end there is a stop collar 36 tions. (Fig. 3)-42are-generally circularv in-plan and are. apertured and straddle the overlapping portions 44 of the blades which are sandwiched and pivoted between the furcations; There? is: a1 head'edll assembly' pin 146 `provided' here and 1 it l extends tlir'ough holes nthe `furcations andk holesV in the blades andfish'eldlin positionb'y, aicotterE key 48;

The motorfhousingfor gear box is of any suitablesectional construction-and-is denoted asa.unitf.by thefnu meral 50: A suitable electric motor= 52is-1connedxth`ere= in and drives a-worm shaft 54`journalediat one end 'in a suitablebearing S6 (Fig. 1.); 'I'hefgearian'clca'rnz-meansl comprises a `worm gear 58 keyedfori rotation' onuansuit'-V able shaft 60'freely turnableinibearingsZKFigt.291. This gear is combined with a camV into at single `unitrand the cam is denotedat 64 andfis a perimeterous:spirallingtypc as bestsseenzin Figs; l and .2 withrtheprojectingor` terminal portion denotedat 66'. This;cam obviouslyfhaswiping and operating contact withlthelcooperatings-end= portion 34 of:A thespringb'iased push-.pull'rodor. plunger. 'I'henumeralsfGS'designate shims and suitable-fasteners which serve to-joinV the angedendlZS'ofthe handle to the cooperating end portion of theV gear4 housing; The cushioning washers 38 are there to taker care of the recoil action/asis obvious.

Reverting to the mode of hinging the'bladefportions. 16, it should be noted'ithat two sets or pairsof. openings are provided; namely, the outer ones 21` through`v which the hinge pins 20 have been passed (in thelmanner shown Fig. 1) andthe inner ones 21a which may; be.v brought into use when necessary or desired. It follows lthatisince these openings 21y and 21A are-properlyV elongatedgthe necessary operating play between parts'is`effectually5 had.

In operationit can be readily seen thatwhen thespiralperimetered friction cam is in a position (see Fig; 1) where its maximum terminal portionl 66 is. inzcontact with the end of the push-pull rod, the shean blades-will be forced open. As the turn of the gear continues. the end of the push-pull rod suddenly returns tofthe minimum point of the spiral by way of the release of theftensioned spring and the blades are then closed. As the gear. continues to turn it will thus activate the push-pull; rod 32 `longitudinally each time it revolves, said. gear: receiving its thrust or operating action through the' wormL gear fromthe fractional horsepower electric motor. The gear ratio and pitch of teeth inthe worml gear and shaft. should be such that whenthe motor is runningatnormal speed the spiral perimetered gear will be'revolvingat approximately 150- revolutions per minute. An electric extension cord 72 serves to supply current to the electric motor through or by way of a variable speed switch 74 so that the action of clipping can bey changed to suit. each individual operator. The casing. 50'as before stated ispreferably made in two separate parts fastened together by screws. It is obvious that other modifications of gearing could be used to turn the gearing and that such possible gearing, if properly powered, could turn; the gears slow enough that more than one hump could be builtf onV the perimeter to activate the push-pull rod a likel-num'ber of times during each revolution.

Although efforts have been made by others working with powered tools, it will be evident by comparing that the instant construction is safer for the operator since the blades are not closed by any gearedpower action, but only by the actionlof releasedtension of the coil spring actuated push-pull rod properly and' adjustablymounted in the. hollow handle. The construction shown has immediate action on its closing movement and' deliberate action on its powered action of opening. Incertain known prior art adaptations both closing and opening speeds are. theV same and acontinuation` of the same geared orV direct speed action. The transmission and release of power is herein effectually activated by practical an'd better-y mechanical means and use' of forces' and in` such a' manner thatf thee problemA ofA clogging or breaking the equipment by way. of foreign objects is virtually eliminated. It is further emphasized that the blades are activated by power by way of-7 the center pin connection between the blades and the spring biased push-pull rod. This is an improvement over any similar adaptation or arrangement requiring the use of activation of handles connected to crossed blades-ofthe well known scissorsyllhe foregoing isi-considered aslillustrativeV only. of the principles of the.. invention.- Further, since numerous modifications and changes willA readily occur to those skilled-in the-art," itis"=not.desired to limit theinventon to the exact constructionand operation` shown and described, and accordingly, all'suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. Automatically operable shears forV use lby hand comprising ahandle, afpair. of cutting blades having limited inner end portionsA overlapping eachl otherv in alignment with the axis of said handle, one' blade being hingedly mounted on the distal end-of the handle to the left of the axisof the handle, the other blade being likewise hingedly mounted but to-the right of` said axis, an-encased prime mover mounted' for operation on thel proximal end of saidY handle, operating meansbetween the primer mover and blades, said means serving rst to spread and open the blades by power delivered posttively and directly from the prime mover tothe blades` and serving, secondly, andv intermittently to` quick-close the blades during which closing step the power cycle andattending drive-action is momentarily released, whereby said bladesarefopened4v progressively but deliberately but are closed speedily and quickly without. ever overloadingthe motor, said operatingI means. embodyingA a power-pushed spring-retarded push-pullrod? mounted for reciprocationA in' the bore ofsaid handle, the forward end of said rod' being pivotally connected to-the overlapping' portions of said blades so that when the rod slides and projects forwardly the blades spread apart and open, and when the rod slides' rearwardly and retracts' the blades come together and close; av coil spring cooperating with the rod and handle for retracting the rod, andpower driven means carried by the handle for projecting the rod and tensioning and cockingsaid spring, said'powerdriven means comprising an encased electric motor the casing of which is mounted on the proximal endA ofv said handle, a gear mounted for rotating in the casing andv having a marginal cam having cooperative driving and` releasing engagementl with the adjacent end of saidY rod, and an operating connection between the motor andfgear.

2. Automatically operable. shears comprising a tubular handletheV ends of the bore of which are open, the distal endof said handle having a forked head, one fork arm being situated to the left, of the axis of the bore and the other fork arm to the right of said axis, a pair of cutting blades, having end portions adjacent to said head and hinged for cooperative opening and closing movement on their respective fork arms, portions of said blades between said arms overlapping each other in alignment with the axis of said bore, a bushing adjustably mounted in the leading end of said bore and' providing a rod bearing, a push-pull rod slidable back and forth in the bearing and bore of said' handle, the leading end of said rod being bifurcated, the furcations which are thus provided embracing and being pivotally joined to said overlapping blade portions, the trailing end of said rod projecting through and beyond the corresponding end of said bore for actuation, a coil' spring in the` bore encircling the rod and bearing, at one end against the bushing and at the other end against a stopcollar provided! therefor on said rod, and' automatically operable means mounted' on the proximal end of said handle for alternatively pushing said rod to tension and cock the spring and then releasing said spring and rod.

3. The structure defined in claim 2, and wherein said means comprises a gear box removably bolted on the handle, a gear mounted for rotation in said gear box and having a spiral-perimeter-cam marginally cooperable with the adjacent end of said push-pull rod, an electric motor coniined in said gear box, and a Worm-shaft carried and operable by said motor and meshed with said gear.

4. An automatically operable pair of shears comprising a tubular handle having a bore extending therethrough, the distal end of said bore having a bearing, said distal end also having a fork head embodying fork arms, one fork arm situated to the left of the axis of said bore and the other fork arm to the right of said axis, a pair of cutting blades having portions thereof overlapping each other in a position [between the respective fork arms, the end portions of said blades adjacent to said fork arms having elongated selectively usable pairs of slots, one slot of each pair on each blade being separably and hingedly connected to the cooperating end portion of the associated fork arm, a push-pull rod slidable back and forth in the bore of said handle with the distal end operable in the bearing at the distal end of the handle, said distal end being bifurcated, the furcations being pivotally joined to said overlapping blade portions, the trailing end of said rod projecting through and beyond the corresponding end of the bore, a coil spring in said bore encircling a rod and under tension and lbearing at one end against said bearing and the other end against a stop shoulder which is provided on said rod and which is coniined for operation inthe adjacent end portion of said bore, an automatically operable means mounted on the proximal end of said handle for alternatively pushing said rod to tension and cock the spring and then releasing the spring and rod, said means comprising a gear box removably bolted on the proximal end of the handle, a gear mounted for rotation in said gear box and having a spiral-perimeterfcam marginally cooperable with the adjacent end of said push-pull rod, an electric motor coniined for operation in. said gear box, and a Worm shaft carried by said motor and operably engaged with said gear.

References Cited in the file of this patent UNITED STATES PATENTS 912,408 Place Feb. 16, 1909 2,348,895 Gaudio May 16, 1944 2,580,831 Persak Ian. 1, 1952 2,777,196 Zoetemelk Ian. 15, 1957 

